23 USC 137 - Fringe and corridor parking facilities

(a) The Secretary may approve as a project on a Federal-aid highway the acquisition of land adjacent to the right-of-way outside a central business district, as defined by the Secretary, and the construction of publicly owned parking facilities thereon or within such right-of-way, including the use of the air space above and below the established grade line of the highway pavement, to serve an urban area of fifty thousand population or more. Such parking facility shall be located and designed in conjunction with existing or planned public transportation facilities. In the event fees are charged for the use of any such facility, the rate thereof shall not be in excess of that required for maintenance and operation (including compensation to any person for operating such facility).
(b) The Secretary shall not approve any project under this section until
(1) he has determined that the State, or the political subdivision thereof, where such project is to be located, or any agency or instrumentality of such State or political subdivision, has the authority and capability of constructing, maintaining, and operating the facility;
(2) he has entered into an agreement governing the financing, maintenance, and operation of the parking facility with such State, political subdivision, agency, or instrumentality, including necessary requirements to insure that adequate public transportation services will be available to persons using such facility; and
(3) he has approved design standards for constructing such facility developed in cooperation with the State transportation department.
(c) The term parking facilities for purposes of this section shall include access roads, buildings, structures, equipment, improvements, and interests in lands.
(d) Nothing in this section, or in any rule or regulation issued under this section, or in any agreement required by this section, shall prohibit
(1)  any State, political subdivision, or agency or instrumentality thereof, from contracting with any person to operate any parking facility constructed under this section, or
(2)  any such person from so operating such facility.
(e) The Secretary shall not approve any project under this section unless he determines that it is based on a continuing comprehensive transportation planning process carried on in accordance with section 134 of this title.
(f) 
(1) The Secretary may approve for Federal financial assistance from funds apportioned under section 104 (b)(4), projects for designating existing facilities, or for acquisition of rights of way or construction of new facilities, for use as preferential parking for carpools, provided that such facilities
(A)  are located outside of a central business district and within an interstate highway corridor, and
(B)  have as their primary purpose the reduction of vehicular traffic on the interstate highway.
(2) Nothing in this subsection, or in any rule or regulation issued under this subsection, or in any agreement required by this subsection, shall prohibit
(A)  any State, political subdivision, or agency or instrumentality thereof, from contracting with any person to operate any parking facility designated or constructed under this subsection, or
(B)  any such person from so operating such facility. Any fees charged for the use of any such facility in connection with the purpose of this subsection shall not be in excess of the amount required for operation and maintenance, including compensation to any person for operating the facility.
(3) For the purposes of this subsection, the terms facilities and parking facilities are synonymous and shall have the same meaning given parking facilities in subsection (c) of this section.